As electronic and electric technology develops continuously, power semiconductor devices, which are used as basic electronic components for power control and transformation in electronic and electric systems, have received more and more attention. The technical requirements for improving the performance of power semiconductor devices are mainly embodied in aspects such as integrability, high withstand voltage and high current of the devices, and good isolation from the low-voltage circuit portion. Besides the type of the power semiconductor device, the structure and manufacturing process of a power semiconductor device is also an important influencing factor for high voltage and high current withstand capability of a power integrated circuit.
As the theoretical research and manufacturing technology of power semiconductor devices evolved continuously, insulated gate bipolar transistors (IGBTs) emerged in the 1980s. IGBTs integrate the high current-handling capability of high-voltage triodes and the gate voltage control features of insulated gate field effect transistors (IGFETs), and have advantages such as high input impedance, high switching speed, low driving power, high current driving capability, and low on-resistance, etc. They are almost ideal power semiconductor devices, and have broad development and application prospects.
After the requirements for integrability, high voltage withstand and high current of power semiconductor devices were met, the isolation capability became the top challenge. In that situation, Silicon On Insulator (SOI) technology emerged. With a unique buried insulating layer in SOI, the device is completely isolated from the substrate, the parasitic effect of the silicon device is greatly reduced, and the performance of the device and circuit is significantly improved. A Silicon-On-Insulator Lateral Insulated-Gate Bipolar Transistor (SOI-LIGBT) is a typical SOI-based device, which has advantages including high withstand voltage, high current driving capability, high switching speed, and low power loss, etc. SOI-LIGBTs have gradually become core electronic components for power integrated circuits, and have been widely used in conversion systems with 600V or higher DC voltage, such as AC motors, inverters, switching power supply units, lighting circuits, and traction drive systems, etc.
Compared with longitudinal devices, the current density of SOI-LIGBT devices is usually not high enough. Usually, to solve that problem, the area of the lateral devices is increased to obtain higher current driving capability. However, the increased area is implemented at the cost of consumption of larger chip area, and results in increased cost.
The present invention discloses a high-current N-type SOI-LIGBT, which can attain much higher current density when compared with conventional N-type SOI-LIGBTs that have the same area.